JPS601834B2 - Pulse width modulation inverter device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a pulse width modulation inverter device.

A conventional pulse width modulation inverter was constructed as shown in FIG.

In FIG. 1, reference numeral 1 denotes a DC power source, and this DC power source 1' is connected to both ends of electric valves 2 and 3 that are connected in series.

The electric valves 2, 3 are made of transistors, for example.
Reference numeral 4 is a load connected between the intermediate portion of the DC power supply 1 and the electric valves 2 and 3. Now, by alternately igniting the electric valves 2 and 3, a waveform as shown in FIG. 2 is obtained, thereby controlling the output waveform and effective value.

However, this configuration has the drawback of large harmonic ripples, as seen in FIG.

The object of the present invention is to obtain a pulse width modulation inverter device with less harmonic ripple, which solves the above-mentioned drawbacks.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 3, the code 1 is the same DC power source as in FIG.
2, 2a, 3, and 3a are electric valves each made of, for example, a transistor, 4 is a load, and 5 is an autotransformer.

The electric valves 2 and 3 are connected in series, and the electric valves 2a and 3a, which are connected in direct current to each other, are connected in parallel to the electric valves 2 and 3.
The autotransformer 5 has one terminal a connected between the electric valves 2 a and 3 a, an intermediate tap b between the electric valves 2 and 3, and the other terminal c connected to the load 4.

The load 4 is connected between the terminal c and the intermediate point 0 of the DC power supply 1. Next, the operation of this circuit will be explained.

Now, if a low voltage is required as the output voltage, the fourth
As shown in Figure a, the electric valves 2, 2a and 3, 3a are made into a set, and the electric valves in this set are ignited alternately. The output waveform resulting from this becomes a waveform with a peak value of B as shown in the figure, and the output voltage is lower than when a high voltage is output, which will be described later. In this case, the harmonic ripple contained is the same as that of the slave system, but in the region where the output voltage is low, the system does not operate for a long time and does not pose a problem. On the other hand, when high voltage is required, the electric valve 2 is maintained in the ignition state during the half cycle, and in this state the electric valves 2a and 3a are alternately ignited, the output waveform is as shown in Fig. 4b. As a result, the width of the electric current is the same as the competition.
1) It becomes smaller.

As a result, the ripples are also reduced, and a pulse width modulation inverter device with small harmonic ripples included in the output can be obtained.

In the above embodiment, the case where the other end C of the autotransformer 5 is directly connected to the load 4 has been explained, but as shown in FIG. 2a and 3a, the other end C to the connection point of electric valves 2 and 3, and the intermediate tap b to the load 4, the same effect as this embodiment can be achieved, and the harmonic ripple It is possible to provide a pulse width modulation inverter device with less.

As described above, according to the present invention, it is possible to provide a pulse width modulation inverter device that solves the conventional drawbacks with a simple circuit configuration and has less harmonic ripple.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing the configuration of a conventional pulse width modulation inverter device, FIG. 2 is a diagram showing the operation and output waveform of an electric valve according to the circuit of FIG. 1, and FIG. An electric circuit diagram showing the configuration of a pulse width modulation inverter device according to an embodiment of the invention, FIGS. FIG. 3 is an electrical circuit diagram showing the configuration of a pulse width modulation inverter device according to another embodiment of the invention. 1...DC power supply, 2, 2a, 3, 3a...
Electric valve, 4...Load, 5...Autotransformer, a, c...Terminal, b...Intermediate tap. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. first and second electric valves connected in series;
third and fourth electric valves connected in series with each other and in parallel with said first and second electric valves; an autotransformer having an intermediate tap; and said first and second electric valves. 2 electric valves and a DC power supply connected between both terminals of the third and fourth electric valves, and the autotransformer has one end connected to the connection point of the third and fourth electric valves. , the other end is connected to a load, and the intermediate tap is connected to a connection point of the first and second electric valves, respectively. 2 The autotransformer has one end connected to a connection point between the third and fourth electric valves, the other end to a connection point between the first and second electric valves, and the intermediate tap connected to the load. A pulse width modulation inverter device according to claim 1, comprising: